The present invention relates generally to lubrication apparatus and method for an overhead conveyor system, and more particularly, to a lubrication apparatus method for an overhead chain and trolley conveyor system that selectively lubricates targets as they are presented.
Overhead xe2x80x9cchain and trolleyxe2x80x9d conveyor systems are widely used in manufacturing and material handling operations. For instance, such systems can be designed to carry objects ranging from washing machines and car parts to poultry, and are used to move the objects through a plant in assembly-line like fashion. The conveyor system typically includes an elevated suspended guide rail, which is a beam having an I, T, L or other channel shape, and a series of interconnected wheeled trolley elements which hang from the beam, coupled to each other through a flexible chain-like linkage (xe2x80x9cchainsxe2x80x9d). In the I-beam rail configuration, which is the most popular, the trolleys have a pair of bearing wheels which ride on the upper surface of the lower flange of the I-beam. The wheels extend from a yoke frame that girdles beneath and is centered on the web of the I-beam. The wheels are spaced from each other by a width that is just slightly greater than the thickness of the web of the I-beam, such that one wheel cannot slip off the lower flange, as the opposed wheel will encounter the web of the I-beam. The chain-like linkage is propelled, usually by a powered sprocket. In turn, the linkage moves the trolleys along the beam or guide rail.
In service, the trolley wheels and chains begin to wear over time. Points of wear include the bearing races within each wheel, and the joints between chain linkages. After a relatively short period of time, such as one year, the trolley and chains must be replaced to avoid the entire conveyor system binding and bringing the conveyor to a sudden halt. This frequent replacement can be an enormous expense for companies, especially if the trolley and linkages support very heavy objects, or if the conveyor system is lengthy. Lighter duty chain and trolley conveyors typically cost from $1 to $20 per foot, and may be used in plants having several miles of conveyors. Thus, the cost of replacing the chain and trolleys is very expensive, even without the costs associated with conveyor down-time and labor. It is very advantageous for companies to prolong the life of their overhead conveyors by regularly applying a lubricant thereto, as it is less costly than replacing the conveyor. This is especially true for the more expensive heavy-duty chains and trolleys.
Conventional lubrication systems for chain and trolleys have the disadvantage of applying a lubricant to an anticipated target such as a chain link or bearing race. For example, an upstream sensor will sense a particular target, and cause a lubricant to be released onto a downstream target. Because the targets are repetitive and equally spaced, it is anticipated that there will be a downstream target present to receive the lubricant when the upstream target is sensed. However, if there is a missing or damaged trolley, the lubricant will be released, but there will be no target present to receive it. Instead, the lubricant will either collect on the beam or drip down onto the conveyed object. In either case, lubricant will be wasted and applied to surfaces or objects other than a desired target. Furthermore, if the trolleys are sensed and only occur every few feet with several chain links in between, rather than a trolley for every chain link, then lubricant is not being applied to all of the chain links.
In many industries it is important to avoid having lubricant drip from the overhead conveyor onto the objects being conveyed. For example, in poultry processing plants, the conveyor system is used to carry a bird to and from the numerous work-stations as the bird is processed. Because the conveyed material is a food product, an essential performance criteria is that the conveyor and bird are kept clean of oil and other types of contamination.
Furthermore, mis-aligned trolleys cause not only misapplication of lubricant, but also hazards for the equipment that applies the lubricant, employees and/or equipment located below the apparatus. For example, if a trolley is missing a wheel and hanging out of alignment with the beam or rail, it can contact the lubrication apparatus and cause damage by bending the apparatus or knocking it free from the beam. The lubrication apparatuses need to withstand impact from mis-aligned trolleys.
In addition, lubrication apparatuses need to be easily replaceable and moveable for maintenance or other reasons. However, conventional lubrication apparatuses have the disadvantage of being attached to the beam in a manner that renders them impractical to relocate, and which lessens beam integrity. For example, holes are usually drilled into the beam so that the apparatus can be bolted thereon. Therefore, it is undesirable to relocate a conventional apparatus because new holes have to be placed in the beam each time such apparatus is moved.
Therefore, in view of the problems associated with the conventional type of overhead xe2x80x9cchain and trolleyxe2x80x9d conveyor it is an object of the present invention to provide such an apparatus that will neither miss targets nor apply lubricant to objects other than the target. It is another object of the invention to provide a lubrication apparatus that can withstand impact from a mis-aligned trolley. It is yet another object of the invention to provide a lubrication apparatus that is can be readily relocated and has an attachment means that does not affect the structural integrity of the beam.
These and other objectives are met by the lubrication apparatus of the present invention. The lubrication apparatus is mounted to the beam using a mounting assembly. In one aspect of the invention, the mounting assembly uses hook members to attach the apparatus to the beam.
Depending on the configuration of the chain and trolley apparatus, there will be at least one bracket attached to the mounting assembly. The bracket or brackets hang adjacent the mounting assembly. Preferably, the brackets are pivotally attached to the apparatus so that they can readily move out of the way if a mis-aligned trolley hits the bracket. The brackets are further provided with flanges to direct any mis-aligned trolleys past the brackets without significant damage to the bracket.
At least one pump is attached to the apparatus, preferably to a bracket, the pump sending a lubricant to a nozzle that is directed to a target. Of course, one should realize that there may be more than one target, so a pump and nozzle is supplied for each separate target.
Lubricant is ejected from the nozzle when a photo-electric sensor attached to the apparatus senses the target. A control system is attached to the mounting assembly for controlling the air supply and pump operation.
In one aspect of the invention, an air supply is used to supply an air flow to each pump and to each nozzle to aid in ejecting the lubricant from the nozzle.
A method for lubricating a chain and trolley apparatus begins with positioning a lubricant dispersion device to project the lubricant at the target. Next, the target is sensed and lubricant is dispersed to the target. The dispersion of lubricant only occurs when a target is presented.
The present invention will be better understood from the following detailed description of the invention, read in connection with the drawings as hereinafter described.